Leaf-spring.



Patented January 3, 1905.

PATENT OFFICE.

STEPHEN WV. BALDWIN, OF NEW YORK, N. Y.

LEAF-SPRING.

SPECIFICATION forming part of Letters Patent No. 779,020, dated January 3, 1905.

Application filed arch 14, 1904. Serial No. 198,080.

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Be it known that I, STEPHEN W. BALDWIN, a citizen of the United States, residing in New York city, Manhattan borough, in the county n of New York and AState of New York, have invented certain new and useful Improvements in Leaf-Springs, of which the following is a specification.

This invention relates to leaf-springs, and has for an object to provide improved springs, and more especially springs adapted for heavy service-as, for instance, in railway equipment, particularly locomotive-springs.

One of the objects of the present improvement is to furnish a spring' of such construction that the several leaves therein will have the stresses so distributed through their different portions as to favor longevity in the individual leaves and in the spring' and the spring as a whole to have the stresses so distributed as to favor its longevity and also of the individual leaves. Y

My invention is illustrated in the drawings accompanying' and forming a part of this specification, and wherein- Figure 1 is a side view of an assembled spring, one end broken away. Fig. 2 shows the same as viewed from the under side. Fig. 3 is an enlarged cross-section of a number of assembled leaves, and Fig. 4 is a still more enlarged cross-section of portions of a number of assembled leaves.

ln Fig'. 1 is a side view of a portion of an ordinary leaf-spring' of the class used in railway-work, especially in locomotive-spring's. The several leaves or plates of the spring (designated in a general way by 6) are assembled together and in the present illustration held in place by a band or yoke, indicated in a general way by 7, the several leaves of the spring' being' assembled one upon the other and forced into contact and held together by the yoke-in the present illustration by a wedg'e 8, resting upon a plate 9, interposed between the yoke and the outermost leaf of the pile-in the present instance the upper leaf. In a concurrently-pending application, Serial No. 198,081, filed March 14, 1904, I have illustrated and described animprovement in means for assembling and holding' together spring-leaves which is readily adaptable for use in springs made in accordance with the improved system of spring manufacture herein and which means is herein illustrated in a general Way. Pressure applied to the end of the spring-as, for instance, at. the region of the arrow IOMoperat'es in 'a well-known manner to cause a deiiection of all of the spring-leaves, provided, of course, the pressure so applied be sufiiciently great.

A leading' feature of my present improvement is the peculiar relation and proportionment of the various bearing-faces of the spring plates or leaves. Each leaf according to the present improvements will have longitudinal bearing-faces, and in the illustration herein there will be a centrally-disposed longitudinal bearing-'face of considerable cross-sectional Width on each side and bearing-faces along the edge of the plates and disposed substantially parallel to the central bearing-face. The edge bearing-faces are when the spring is considered in its cross-section upon a different plane from that of the central portion. It is desirable for several purposes, among' which is interchangeability, to permit a certain amount of clear space in certain portions between the plates, making longitudinal clear spaces. Thisis accomplished in the form of the invention illustrated by having the portions of the plate intermediate the middle portion and the edge portions inclined relatively thereto and by having the various bearing-faces in parallelism. The plates may be made of substantially uniform thickness throughout and may have upon one side a longitudinal face curved about-an aXis transverse to its length and flanked by longitudinal faces curved about an airis parallel to said former axis, and the other side of the plate may have a central longitudinal face narrower than the corresponding face upon the formerside and curved about an aXis parallel to the axis thereof and iianked by longitudinal faces wider than the corresponding faces upon the former side and curved about an axis parallel to the axis thereof, said Hanking faces being spaced from the flanked face by spaces wider than such flanking faces, the axes all occupying the same plane. The edge or flanking faces are shown narrower than the middle portions. When the plates are piled up one upon the other, the various faces will give eflicient bearing at the central portions in the cross-sectional direction of the spring and will produce non-bearing portions contiguous to such bearing portions. A practicable form of so constructing the spring is illustrated in Fig. 3, in which is represented in cross-sectional form-three spring-leaves assembled one upon the other. For purposes of comparison the dotted lines 11 represent approximately the so-called neutral axes of the spring-leaves. By diagrammatic reference-lines designated by 12, 13, and 14:, respectively, are represented the middle, the intermediate, and the edge portions, respectively, of the spring-leaf. The intermediate portion 13 is inclined with relation to the portion 12, and the edge portion 111 is in substantial parallelism with the middle portion 12.

Also the leaves or plates are preferably so shaped and proportioned as to leave a clear space between said intermediate portions 13 13 of the leaves of the spring when assembled, and in their assemblage they are broughtinto such a relation as to the bearing of one upon the other that the principal weight or force is transmitted through the surfaces of the parallelly-disposed portions. By reference to Fig'. 4 it will be seen that the face 15 of the portion 14 is narrower than the face 16, the dotted line 17 drawing attention to the inner margins of the faces 15 and the dotted line 18 to those of faces 16. The faces 19 of the middle portions are shown in Fig. 3 as wider than the faces 2() of such portions, the dotted lines 21 drawing attention to the margins of the faces 19 and the dotted lines 22 to those of the faces 20. By thus having the upper faces of the middle portions narrower than the under faces of such portions and by having the upper faces of the edge portions wider than the under faces of such portions the clear space referred to is had, which space is designated by the reference character 25. Each of the leaves or plates is illustrated herein of uniform thickness throughout its length, and the leaves are illustrated of uniform thickness one relative to the other in i the spring.

By reason of the conformation of the springleaf as to its cross-sectional form the height between the faces of the central portion of the plate which is in the illustration in Fig. 3 farthest removed from the representation of the neutral axis will be relatively greater than the distance between the edge bearingface upon the same side of the plate and such neutral axis, and by way of illustration it will 'be seen that the height of the space 30 is relatively less than the height of the space 31 by a distance equal to the inclination of the Zone or inclined portion 13. tance 30 substantially' less than the distance 31 it will be observed that'on the flexure of the spring-leaf the relative extension of said leaf at the point 32 will naturally bedistinctly less than it will be along the upper side of the leaf-as, for instance, at 30. By this means the tendency to open incipient cracks along the edge 32 is largely reduced, the middle portion of the spring--as, for instance, along the surface 20'bei'ng subjected to a relatively greater longitudinal extension. This, it will be evident, is accompanied by a concurrent tendency to a greater compression along the lower edge 33 of the leaf and by a relatively less tendency to compression along the lower surface 19 of the middle Zone 12.

The ends of the leaves are illustrated of equal.

thickness with the body portion, but narrowed by bevels 35.

BY making the dis i The effect of' the peculiar organization of the several cross-sectional components of the spring-leaf embodied in this invention is to control and modify the location of the neutral axis during the operation of the spring as a whole, to reduce the tendency of incipient cracking in those portions of the leaf wherev such dangeris in ordinary forms of leaves largely increased, and concurrently to place the heaviest and most severe part of` the work upon those portions which are, by reason of the peculiar organization of the spring best able to sustain the principal part of the load or burden.

In built-up leaf-springs which have transversely-curved plates the sliding action of one plate upon the other tends to dislocate the entire spring and throw it out of proper working order, frequently giving to the spring a curve in its entirebody; but in the present construction all the leaves are kept parallel or horizontal notwithstanding some sidewise slipping of one upon the other. The bearingfaces being parallel, any slipping or move,-

ment of one or more plates relatively to the l entire body of plates or, in fact, a sidewise slipping of all. the platesrone relatively to the other will still leave the spring as a whole so that the line of action will not be changed angularly.

My present improvement, besides the ad vantages t o be had in use, also has the advantage of providing for the economical manufacture of leaf-springs bythe making of the plates of such a form that while they control and distribute the strains and internal stresses with especial eiiiciency they can be manufactured according to the interchangeable system, so that in practice springs may be assembled from leaves previously prepared and kept in stock, a result not heretofore found feasible in this class of work, and broken leaves may be similarly replaced without fitting.

My improved spring being adapted to be made, of leaves of uniform thickness from end IOO to end, the plates for the` leaves may be rolled to the proper size and form, varying in length according to ascale or graduation which in any particular line of service will be ascertained by practical tests and investigation.

In my improved spring the parallelism of the several bearing surfaces has the additional advantage of making it more practicable to construct and maintain the rolls by which the plates are made and shaped if rolls are employed in their manufacture.

In this description it has been found convenient in referring to the several parts to speak of them as seen upon the sheet and not with a view of limitation.

Having thus described my invention, I

claim@ l. A spring comprised of a number of plates each having an engaging face at the top and bottom respectively of its middle portion throughout substantially its entire length, an engaging face at the top and bottom respectively of each edge portion, and an inclined portion between the middle portion and each edge portion having non-engaging faces upon its top and bottom respectively; the said engaging faces of the respective plates engaging each other and the non-engaging faces forming open spaces.

2. A spring comprised of a number of assembled plates each having a bearing-face at the top and bottom of its middle portion throughout substantially its entire length, a bearing-face at the top and bottoni of its edges, and clear spaces between the plates intermediate such bearing-faces.

3. A spring comprised of a number of leaves each having a central longitudinally-disposed face upon one side and a similar but wider face upon the other side, longitudinally-disposed faces upon the former side at the edges, and similar but narrower faces upon the latter side, the said faces of one leaf engaging the said faces of the adjacent leaves.

4. A spring built up of anumber of leaves uniform in thickness and bearing one upon the other at the central longitudinal portion and the edges only, thereby leaving openings between such bearing portions.

An elliptical spring embodying a number of leaves piled one upon the other, each leaf having in cross-section its edges lower than its center and the contact-faces between the various leaves being in 'parallelism and presenting in cross-section right lines.

6. A spring-leaf embodying in cross-section a substantially straight middle portion, substantially straight edge portions, and inclined intermediate portions.

7. A spring-leaf having in cross-section a straight middle portion,l straight edge portions, and inclined intermediate portions, the face of the middle portion upon one side having greater width than the face thereof upon the opposite side, and the faces of the edge portions upon the said former side having less width than the faces thereof upon the said latter side.

8. A spring-leaf having upon one side a longitudinal face flanked by longitudinal faces, and upon the other side a longitudinal face narrower than the corresponding face upon the former side and anked by wider longitudinal faces.

9. A spring-leaf having substantially uniform thickness throughout, and havinglipon one side a longitudinal face flanked by narrower longitudinal faces, and upon the other side a longitudinal face narrower than the corresponding face upon the former side and flanked by wider longitudinal faces.

10. A spring-leaf having substantially uniform thickness throughout, and having upon one side a longitudinal face curved about an axis transverse to its length and flanked by narrower longitudinal faces curved about an axis parallel to said former axis, and upon the other side a longitudinal face narrower than the corresponding face upon the former side and curved aboutan axis parallel to the axis thereof, and flanked by longitudinal faces wider than the corresponding faces upon the former side and curved about an axis parallel to the axis thereof.

11. A spring-leaf having substantially uniform thickness throughout, and having upon one side a longitudinal face curved about an axis transverse to its length and flanked by narrower longitudinal faces curved about an axis parallel to said former axis, said Hanking faces being spaced from the flanked face; and upon the other side a longitudinal face narrower than the corresponding face upon the former side and curved about an axis parallel to the axis thereof, and flanked by longitudinal faces wider than the corresponding faces upon the former side and curved about an axis parallel to the axis thereof, said flanking faces being' spaced from the flanked face.

12. A spring-leaf having substantially uniform thickness throughout, and having upon one side a longitudinal face curved about an axis transverse to its length and flanked by narrower longitudinal faces curved about an axis parallel to said former axis, said flanking faces being spaced from the flanked face by faces wider than such flanking faces; and upon the other side a longitudinal face narrower than the corresponding face upon the former side and curved about an axis parallel to the axis thereof, and flanked by longitudinal faces wider than the corresponding faces upon the former side and curve-d about an axis parallel to the axis thereof, said flanking faces being spaced from the flanked face by faces wider than such flanking faces. 13. A spring-leaf having upon one side a longitudinal face curved about an axis transverse to its length and flanked by narrower longitudinal faces curved about an axis par- IOO IIO

allel to said former axis, said flanking faces being spaced from the flanked face by faces Wider than such flanking faces; and upon the other side a longitudinal face narrower than the corresponding face upon the former side and curved about an axis parallel to the axis thereof, and flanked by longitudinal faces wider than the corresponding faces upon the former side and curved about an axis parallel to the axis thereof, said flanking faces being spaced from the flanked face by faces wider than such flanking faces, the said axes all occupying the same plane.

14. A spring-leaf having upon one side a longitudinal face curved about an axis transverse to its length and flanked by longitudinal faces curved about an axis parallel to said former axis, said flanking faces being spaced from the flanked face; and upon the other side a longitudinal face narrower than the corresponding face upon the former side and curved about an axis parallel to the axis thereof, and flanked by longitudinal faces, wider than the corresponding faces upon the former side and curved about an axis parallel to the axis thereof, said flanking faces being spaced from the flanked face, the said axes all occupying' the same plane, and the distance between the axes of the flanking faces being equal' to the distance between the axes of the flanked faces.

15. A spring-leaf having upon one side a longitudinal face curved about an axis transverse to its length and flanked by narrower .longitudinal faces curved about an axis parallel to said former axis, said flanking' faces being spaced from the flanked face by faces wider than such flanking faces; and upon the other side a longitudinal face narrower than the corresponding face upon the former side and curved about an axis parallel to the axis thereof, and flanked by longitudinal faces wider than the corresponding faces upon the former side and curved about an axis parallel to the axis thereof, said flanking faces being spaced from the flanked face by faces wider than such flanking faces, the said axes all occupying the same plane, and the distance between the axes of the flanking faces being equal to the distance between the axes of the flanked faces.

16. A spring composed of a number of leaves each having upon one side a longitudinal face curved about an axis transverse to its length and flanked by longitudinal faces curved about an axis parallel to said former axis, said flanking faces being spaced from the flanked face; and upon the other side a longitudinal face narrower than the corresponding face upon the former side and curved about an axis parallel to the axis thereof, and flanked by longitudinal faces wider than the correspondl flanking faces being spaced from the flanked face, the said axes all occupying the same plane, and the distance between the axes of' the flanking faces being equal to the distance between the axes of the flanked faces of the respective leaves, the said curved faces of one leaf engaging the curved faces of adjacent leaves,'and the spacing-faces of one leaf being out of engagement with the spacing-faces of adjacent leaves. l

17. A spring composed of a number of leaves each having upon one side a longitudinal face curved about an axis transverse to its length and flanked by narrower longitudinal faces curved about an axis parallel to said former axis, said flanking' faces being spaced from the flanked face by faces wider than such flanking faces; and upon the other side a longitudinal face narrower than the corresponding face upon the former side and curved about an axis parallel to the axis thereof, and flanked by longitudinal faces lwider than the corresponding faces upon the former side and curved about an axis parallel tothe axis thereof, said flanking faces being spaced from the flanked face' by' faces wider than such flanking faces, the said axes all occupying the same plane, and the distance between the axes of the flanking faces being equal to the distance between the axes of the flanked faces of the respective leaves, the said curved faces of one leaf engaging the curved faces of adjacent leaves, and the spacing-faces of one leaf being out of engagement with the. spacing-faces of adjacent leaves.

18. A spring composed of a number of flat plates each having engaging faces on its middle portion throughout substantially its entire length,` engaging faces on its edge portions IOO and inclined portions between the middle pory STEPHEN W. BALDWIN.

Witnesses:

GHAs. LYON RUSSELL, FRED. J. DOLE.

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